1. Technical Field
The present invention relates to a liquid ejecting apparatus such as an ink jet printer having a liquid ejecting head that ejects liquid inside a pressure chamber through nozzles, by providing pressure fluctuations to the pressure chamber that communicates with the nozzles.
2. Related Art
Liquid ejecting apparatuses have a liquid ejecting head that ejects (discharges) various liquids. Examples of such liquid ejecting apparatuses include, for instance, an image recording apparatus such as an ink jet printer (hereinafter referred to as a printer) which has an ink jet recording head (referred to as a recording head hereinafter) as a liquid ejecting head, and records images or the like by ejecting liquid ink droplets from the nozzles of the recording head and causing one liquid ink droplet to strike a recording medium (ejection target) such as recording paper. Recently, application of such apparatuses has not been limited to only such an image recording apparatus but has been extended to other manufacturing devices. For instance, in display manufacturing devices such as liquid crystal displays, plasma displays, organic EL (Electro Luminescence) displays or FEDs (Field Emission Displays), liquid ejecting apparatuses are used in which various liquid materials such as color materials or electrodes are ejected toward a pixel forming area or an electrode forming area.
In such a recording head, for example, a frame-shape head cover in which a nozzle plate is exposed through an opening, is mounted on a head case so as to protect the nozzle plate from a recording medium which shifts in relation to the recording head (see, for instance, JP-A-2000-190513). So-called multi-head printers have also been proposed in which a plurality of recording heads, having a plurality of nozzles provided in rows as nozzle groups, are arranged and fixed to a head fixing member, such as a sub-carriage, as one head unit.
In the multi-head printers, openings are provided at a sub-carriage, and a plurality of recording heads are inserted through the openings and fixed. Thus, with additional recording heads fixed to a sub-carriage, the sub-carriage will have greater area for openings and thus lose its rigidity. Accordingly, the recording heads mounted in alignment with the sub-carriage having lower rigidity are often displaced from a certain position and the positions of ejected liquid droplets thus deviate more when the sub-carriage is deformed by external force, such as vibration or contact with an ejection target such as a recording medium.
Also, a sub-carriage often has protective protrusions so as to protect the sides and the nozzle plates of the recording heads from a recording medium being transported, or the like. The protective protrusions are mounted at ends parallel to the recording heads in the sub-carriage, and protrude downward close to the nozzle plates of the recording heads (to the side of the recording medium during recording), parallel to the sides of the recording heads. However, since the protective protrusions are arranged outside of and parallel to the recording heads, the recording heads spaced away from the protective protrusions (the center recording heads) are insufficiently protected while the recording heads close to the protective protrusions (the recording heads at the ends of the row) are protected. As a result, when a transported recording medium or the like contacts a recording head, the recording head is displaced by the shock thereby and the impact locations of liquid droplets become less accurate.